Spring Security, versions 4.2.x up to 4.2.12, and older unsupported versions support plain text passwords using PlaintextPasswordEncoder. If an application using an affected version of Spring Security is leveraging PlaintextPasswordEncoder and a user has a null encoded password, a malicious user (or attacker) can authenticate using a password of “null”.

Affected Pivotal Products and Versions

Severity is
low
unless otherwise noted.

Spring Security 4.2 to 4.2.12

Older unsupported versions are also affected

Note that Spring Security 5+ is not impacted by this vulnerability.

Mitigation

Users of affected versions should apply the following mitigation:

4.2.x users should upgrade to 4.2.13

Older versions should upgrade to a supported branch

There are no other mitigation steps necessary.

Credit

This issue was identified and responsibly reported by Tim Büthe and Daniel Neagaru from mytaxi.